Diagnosis Procedure

Regarding Wiring Diagram information, refer to WIRING DIAGRAM .

1. CHECK TORQUE SENSOR POWER SUPPLY CIRCUIT
   
   
   1. Turn ignition switch ON.
   2. Check voltage between EPS control unit harness connector terminals and ground.
      CAUTION:

      Steering wheel is neutral position. (There is no steering force.)

      EPS control unit		-	Voltage
      Connector	Terminal
      M27	18	Ground	Approx. 5 V

   Is the inspection result normal?

   YES 

   GO TO STEP 2  .

   NO 

   Perform the trouble diagnosis for battery power supply circuit. Refer to DIAGNOSIS PROCEDURE .

2. CHECK TORQUE SENSOR GROUND CIRCUIT
   
   
   1. Turn ignition switch OFF.
   2. Check continuity between EPS control unit harness connector terminal and ground.
      CAUTION:

      Steering wheel is neutral position. (There is no steering force.)

      EPS control unit		-	Continuity
      Connector	Terminal
      M27	15	Ground	Yes

   Is the inspection result normal?

   YES 

   GO TO STEP 3  .

   NO 

   Repair open circuit or short to ground or short to power in harness or connectors.

3. CHECK TORQUE SENSOR SIGNAL
   
   
   1. Turn ignition switch OFF to ON.
   2. Check voltage between EPS control unit harness connector terminal and ground.
      CAUTION:

      Steering wheel is neutral position. (There is no steering force.)

      EPS control unit		-	Voltage
      Connector	Terminal
      M27	17	Ground	Approx. 2.5 V
      	16

   3. Start the engine.
   4. Check voltage between EPS control unit harness connector terminal and ground.
      CAUTION:

      Steering wheel is right or left turn.

      EPS control unit		-	Voltage
      Connector	Terminal
      M27	17	Ground	Approx. 1.6 V - 3.4 V (The value is changed according to steering left or right)
      	16

   Is the inspection result normal?

   YES 

   GO TO STEP 4  .

   NO 

   Torque sensor is malfunction. Replace steering column assembly. Refer to REMOVAL AND INSTALLATION .

4. CHECK CONNECTOR
   
   
   1. Turn ignition switch OFF.
   2. Disconnect EPS control unit harness connector.
   3. Check terminal for deformation, disconnection, looseness, and so on. If any malfunction is found, repair or replace terminal.

   Is the inspection result normal?

   YES 

   Replace EPS control unit. Refer to REMOVAL AND INSTALLATION .

   NO 

   Repair or replace the malfunctioning parts.